These Optical Illusions Trick Your Brain With Science

The combination of patterns and colors trick your brain into thinking this still psychedelic swirl is actually moving.

Your eyes are constantly scanning an image, "like a twitchy digital camera continually autofocusing and adjusting the eye’s lens," Gifford writes in the Guardian. This is at least partly responsible for illusions that appear to move, like these wheels.

Images like this elephant, cheekily titled "L'egs-istential Quandary," mess with the brain's skill at detecting patterns and filling visual gaps.

In order to explain how illusions work, Gifford provides a primer on the brain's regions.

Each orange circle is the same size, but the blue circles trick the part of your brain that measures perspective and scale.

The pink and red squares are actually the exact same color. The colored squares surrounding the "pink" and "red" squares your brain into seeing them as different.

Count the number of colors on this cube. See seven? Wrong. The central orange square on the front, and the central brown square on the top are actually the same color.

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These Optical Illusions Trick Your Brain With Science

The combination of patterns and colors trick your brain into thinking this still psychedelic swirl is actually moving.

Your eyes are constantly scanning an image, "like a twitchy digital camera continually autofocusing and adjusting the eye’s lens," Gifford writes in the Guardian. This is at least partly responsible for illusions that appear to move, like these wheels.

Images like this elephant, cheekily titled "L'egs-istential Quandary," mess with the brain's skill at detecting patterns and filling visual gaps.

In order to explain how illusions work, Gifford provides a primer on the brain's regions.

Each orange circle is the same size, but the blue circles trick the part of your brain that measures perspective and scale.

The pink and red squares are actually the exact same color. The colored squares surrounding the "pink" and "red" squares your brain into seeing them as different.

Count the number of colors on this cube. See seven? Wrong. The central orange square on the front, and the central brown square on the top are actually the same color.

The offset blue boxes trick your brain into seeing convergent red lines. In fact, all the lines are parallel.

The Herman Grid is one of the most famous optical illusions. In theory, it works because it tricks the neural process that helps us tell different colors apart.

Kids love being tricked. I know this because over 1,000 UK schoolchildren just voted a book about optical illusions as the winner of this year's Royal Society Young People's Book Prize for science.

Written by Clive Gifford, Eye Benders: The Science of Seeing and Believing explains how your brain sees colors, sizes, shapes, and even movements that do not actually exist. "You cannot explain how many optical illusions work without giving the reader an idea of the brain’s structure and performance," Gifford wrote in The Guardian. And while we still have a lot to learn about how the brain works, Gifford takes care to point out the theories that best explain how we get fooled.

Some of the oldest illusions use simple colors and shapes to trick our sense of scale and perspective. We see equally-sized circles that seem disproportionate, parallel lines that appear to converge, and staircases that never end. Others, like the elephant with the disjoined legs in the gallery above, likely confuse our proclivity to see patterns and fill visual gaps. Illusions that appear to move are perhaps the most interesting. Our brain is continuously rescanning the things it sees, "Like a twitchy digital camera continually autofocusing and adjusting the eye’s lens," says Gifford. Deployed correctly, color contrasts and sequential shapes could trick the scanning process, causing images that come alive as twisting tie-dyes, tumbling leaves, and spinning pinwheels.

Gifford is a journalist and author who has written a staggering number of books, from choose-your-own-adventures, to computer manuals. The Royal Society's Young People's Book Prize recognizes science writing aimed at kids, and is judged by children under age 14.